Looks like we’re finally seeing the EOL for both the Nintendo 3DS and the Wii U.

We would like to inform you that the handling of credit cards and transportation e-money in the Nintendo eShop on the Nintendo 3DS series and Wii U will be terminated at 9:00 a.m. on January 18, 2022 (Tuesday). After the termination, you will no longer be able to add balances using credit cards and transportation e-money from the Nintendo 3DS series and Wii U.

For those of us still playing the 3DS (and the 3 of you still playing on the Wii U), you can still use indirect methods such as adding funds to the 3DS or Wii U via the Nintendo Switch or eShop cards.

source Resetera